The heme involvement in cooperativity of hemoglobin was investigated using Mossbauer spectroscopy. Strained and unstrained forms of model compounds of myoglobin and normal and modified hemoglobins enriched in 57Fe were studied Low temperatures (4.5K) and strong magentic fields (50K Gauss) were used to split the spectra and line shape theory utilizing superoperator technique was used to analyze the data. At least two different heme sites for iron were found in HbA and a new heme structure similar to that of an unstrained model compound was found in the modified Hb system with characteristics similar to Hb. Osler. Bleomycin, a glycopolypeptide with cytotoxic properties, was investigated and two nonequivalent iron sites were found. Electronic relaxation in the Mossbauer spectra differentiated the active from the inactive form. The design and construction of a picosecond laser spectroscopy system has been completed. Experiments are underway for applying this technique to a series of biochemical problems. A serious impairment to the application of a vidicon to detect transient events has been observed and well characterized. A technique has been devised which overcomes this impairment as well as significantly advancing the area of vidicon imaging to pulsed spectroscopy.